var Browser = {
'isIE'      : (navigator.userAgent.indexOf('MSIE') >= 0) && (navigator.userAgent.indexOf('Opera') < 0),
'isFirefox' : navigator.userAgent.indexOf('Firefox') >= 0,
'isGC'      : navigator.userAgent.indexOf('Chrome') >= 0,
'isSafari'  : navigator.userAgent.indexOf('Safari') >= 0,
'isOpera'   : navigator.userAgent.indexOf('Opera') >= 0
};

// if is IE then do it
if (Browser.isIE)
{
    // 渐变2
    var setGradient = (function() {
        //private variables;
        var p_dCanvas = document.createElement('canvas');
        var p_useCanvas = !!( typeof(p_dCanvas.getContext) == 'function');
        var p_dCtx = p_useCanvas?p_dCanvas.getContext('2d'):null;
        var p_isIE = /*@cc_on!@*/false;
        //test if toDataURL() is supported by Canvas since Safari may not support it
        try { p_dCtx.canvas.toDataURL() } catch (err) {
            p_useCanvas = false ;
        };

        if (p_useCanvas) {
            return function (dEl , sColor1 , sColor2 , bRepeatY ) {
                if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);
                if(!dEl) return false;
                var nW = dEl.offsetWidth;
                var nH = dEl.offsetHeight;
                p_dCanvas.width = nW;
                p_dCanvas.height = nH;


                var dGradient;
                var sRepeat;
                // Create gradients
                if(bRepeatY){
                    dGradient = p_dCtx.createLinearGradient(0,0,nW,0);
                    sRepeat = 'repeat-y';
                }else{
                    dGradient = p_dCtx.createLinearGradient(0,0,0,nH);
                    sRepeat = 'repeat-x';
                }

                dGradient.addColorStop(0,sColor1);
                dGradient.addColorStop(1,sColor2);

                p_dCtx.fillStyle = dGradient ;
                p_dCtx.fillRect(0,0,nW,nH);
                var sDataUrl = p_dCtx.canvas.toDataURL('image/png');

                with(dEl.style){
                    backgroundRepeat = sRepeat;
                    backgroundImage = 'url(' + sDataUrl + ')';
                    backgroundColor = sColor2;
                };
            }
        } else if (p_isIE) {

            p_dCanvas = p_useCanvas = p_dCtx = null;
            return function (dEl , sColor1 , sColor2 , bRepeatY) {
                if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);
                if(!dEl) return false;
                dEl.style.zoom = 1;
                var sF = dEl.currentStyle.filter;
                dEl.style.filter += ' ' + ['progid:DXImageTransform.Microsoft.gradient( GradientType=', +(!!bRepeatY ),',enabled=true,startColorstr=',sColor1,', endColorstr=',sColor2,')'].join('');
            };
        } else {

            p_dCanvas = p_useCanvas = p_dCtx = null;
            return function(dEl , sColor1 , sColor2 ){
                if(typeof(dEl) == 'string') dEl = document.getElementById(dEl);
                if(!dEl) return false;
                with(dEl.style){
                backgroundColor = sColor2;
                };
                //alert('your browser does not support gradient effet');
            }
        }
    }
    )();

} else {
    var setGradient = (function() {})();
}

// target = _blank for links
function externallinks() {
    if (!document.getElementsByTagName) return;
    var anchors = document.getElementsByTagName("a");
    for (var i=0; i<anchors.length; i++) {
        var anchor = anchors[i];
        if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "external") {
            anchor.target = "_blank";
        }
    }
}
window.onload = externallinks;